Dental machine



June 16, 1936. N NECHTOW 2,044,255

DENTAL MACHINE Filed Sept. 22, 1934 INVENTOR.

NoeMANN/VEoHTow Patented June 16, 1936 UNITED STATES PATENT 4 Claims.

This invention relates to machines for making models for use in the art of dentistry, suchas models of teeth, cavities, inlays and the like.

In machines of the general class as the one herein referred to, it is well known that reasonably faithful reproductions can be made with the use of an impression in which the customary modeling cement or plastic composition is packed by hand and which, when sufiiciently firm and hard, can be withdrawn from the impression and used as a model.

It is an object of my invention to provide a machine by means of which a model can be cast that will be more exactly like the impression than was possible with the use of machines of the hand operated type and which will function to provide a model the structure of which is of uniform density, exceedingly strong and of great firmness and devoid of air cells and structural weaknesses. l

A still further object is to provide in a machine of this nature means whereby the model may be formed with a shank of any desired size and the same employed to facilitate handling the model and in removing same from the impression.

Another object is to provide a machine in which means are employed for facilitating the application of the impression to or the removal of same from the machine as desired.

A still further object is to provide means whereby the plastic modeling composition will be confined against external displacement from the machine during the process of forming the model.

Another object is to provide means whereby the machine can be readily supplied with a charge of plastic composition and the charge correlated to the impression holder, so that when the machine is placed in motion, the charge will be delivered to the impression in a manner to insure proper compacting of the composition in the impression.

The above, other and further objects of the invention will be apparent from the following description, drawing and appended claims.

The accompanying drawing illustrates a preferred embodiment of the invention, in which Figure 1 is a view in top plan of the machine;

Figure 2 is a vertical longitudinal section through the machine;

Figure 3 is a transverse section taken on the line 3-3 of Figure 2;

Figure 4 is a transverse section taken on the line 4-4 of Figure 2;

Figure 5 is a section on a somewhat larger scale of the casting chamber showing the relationship of the charge holder to the impression holder, the charge having been centrifugally distributed to the impression.

In carrying the invention into practice, use is made of a rotary support I 0 which, in the present embodiment, is in the form of an arm of suitable length and width to constitute a mounting means for other structural parts 'of the invention which I will describe presently. The arm is provided with a shaft ll of a form which can beclamped firmlyin a lathe chuck (not shown), whereby the arm can be rotated at a speed and in such manner'as to effect operative distribution of the plastic modeling composition to the impression during the process of forming the model. At one end, the arm is formed with a longitudinal slot l2 through which the clamp screw l3 of a counterweight Mpasses the screw serving to hold the weight in an intended position of longitudinal adjustment relatively to the opposite end of said arm.

At the opposite end of the arm I0 is a casting chamber assembly l5, the same essentially consisting of a horizontally disposed barrel I6 which is open at its end towards theweight l4 and closed at its opposite end by a removable cap H, the latter having a set of radial clamp screws l8 which are adjustable through the flange IQ of the cap and against the external walls of an impression holder 20. This impression holder may be of any well known construction that will render it suitable for the purpose it is to serve. It is shown as consisting of a metallic cylinder which is concentrically disposed in the barrel iii, the length of the cylinder being appreciably less than that of the barrel, and contained therein is an impression 2| of the customary material, for which no claim is made. Telescopically connected with the cylinder is a hollow tube 22 which is adapted to form a continuation of the cavity 23 in the impression 2|. It is by means of the tube, and its relationship to the impression, that the model to be formed may have formed thereon as an integral part thereof a shank-like portion of any desired length.

The barrel l6 may be attached to the'arm H) in any suitable Well known manner, and as illus trated, said arm is provided with a vertical post 24 which carries a horizontally disposed open ended tube 25, whose outer end is formed with an annular series of stop lugs 26. Removably contained in the tube 25 is a cylindrical charge holder 21, the same adapted to frictionally engage the inner Walls of the tube 25 and to coact with the stop lugs 26, whereby to limit the movement in one direction of the charge holder. The outer end of the charge holder is spaced apart from the inner end of the impression holder 20 so that an air gap G is formed between the latter and the former. It will also be noted that the holder 25 is coaxially related to the impression holder when the parts are combined with each other as intended during the process of making a model of the impression 2|.

In operation, the cap I! is removed from the barrel I6 and the impression holder with the impression 2| clamped in the position shownin Figures 2 and 5 of the drawing. The aforementioned holder 21 is removed from the tube 25 and supplied with plaster-of-Paris or any one of the well known modeling cements or compounds and the holder then readjusted to the positionisho'wn in Figure 2. It will be noted that the inner walls of the barrel 16 are entirely spaced apart from the external walls of the tube '2 5, whereby to provide a continuous air space S between the parts.

Assuming now that the shaft H has been securely attached to a rotary machine, such as a lathe or the like and the machine placed in motion'to revolve the arm II! at the intended speed, it follows that the modeling composition contained in the holder 21 will be forced in an outward direc-' tion from the holder by centrifugal force and delivered into the impression 21, whereby a model will be cast from the impression which will be in exact likeness thereof. Excess moisture contained in the modeling compound can freely escape from the casting chamber during the oper ation of discharging the compoundinto the impression. It follows also that in order that air may readily escape from the impression as the modeling compound is being thrown into the impression, the space between the walls of the barrel l6 and the holder 21 is entirely open as aforementioned. By correlating the impression with the modeling compound as herein provided for, the compound will be closely compacted in the impression as the compound is building up therein, and it follows that air and excess moisture contained in the compound will be evacuated therefrom, so that the finished model will be of uniform density throughout and devoid of those structural weaknesses which heretofore and particularly in the making of models with the handactuated type of machine could not be avoided.

The tube 22 may be constructed of paper or the like rolled to provide a tube of the desired length and placed around the impression holder 20. When formed and applied as just'stated, the modeling compound will build up therein as the model is being made, and by reference to Figure 5, it can be assumed that the model has been completed and that same is provided with a shank M of the length desired.

The outer end of the barrel I6 is provided with an annular series of bayonet slots 28 with which the screws 18 co-act to hold the cap I! operatively applied to the barrel. When the cap is applied as intended, the outer end of the barrel is entirely closed thereby, and during the process of forcing the compound into the impression, the surplus portions of the compound will be impinged against the inner face of the cap and thereby prevented from discharging from the barrel as the arm I0 is being rotated.

To the best of my knowledge, it is new in the art to provide a barrel such, as herein disclosed and to mount therein a holder for a modeling compound and a holder for the impression, from which latter a model is to be formed, the two said holders being spaced apart from each other to provide a gap between the confronting ends of both holders. It is also a novel feature of my invention to mount the holders a suflicient distance apart from each other so that the compound will be discharged more or less directly into the impression and with proper force to cause close compacting of the compound and .an expression therefrom of air, whereby the density of the completed model will be uniformly the same throughout and of a non-porous structure. It is proposed that the mass represented by the assembly I 5 shall be equal in weight to that of the counterpoise [4. However, this will depend to some extent upon the amount of modeling compound contained in the holder 21, and the weight of the impression 2|. It is for this reason, of course, that provision is made for adjusting the weight M longitudinally at one side of th center of rotation of the arm H1.

I show clamp screws 18 as a means of operatively' mounting the impression in the barrel I6 and prefer to use same merely for the reason that they function also as a means of detachably seeming the cap Hi to the barrel. It is, therefore, to be understood that I do not wish to limit myself to the use of these specific structural details, notwithstanding the fact that they per se are believed to be highly useful and patentably novel. This also applies to the form of holder employed for the modeling compound. While the one disclosed herein is decidedly usefuland patentably novel, in that it can be readily re moved from or applied to the machine as desired, it is to be understood that any suitable well known holder-can-be substituted therefor withou' departing from the spirit and intention of the invention;

What is claimed is:

l.' In a dental device of the'class described, a barrel open at one end; a closure cap removably fitted to the opposite end of the barrel; an impression holder carried by the cap; means for removably attaching the cap to the barrel and for supporting the impression holder in the barrel for distribution of modeling material to the impression; a revoluble arm on which the barrel is mounted; and. a holder on the arm for said modeling material, the same disposed at'said open end of the barrel and co-axially related to said impression holder for distribution of said material to saidimpre'ssion when the arm is revolved. 1

2. In a dental device of the class described, a barrel open at one end and provided at its other end with a removable closure cap; an impression holder contained in the barrel at said closure cap; and radial screws carried by the cap and engageable with said barrel to removably secure the cap to the barrel and for supporting the impression holder in a position co-axially of the barrel to enable a plastic modeling material to be distributed to a supported impression from the open end of the barrel.

3. A dental device of the class described comprising a barrel having a removable closure cap at one end, provided with means for removably supporting and disposing an impression holder within the'barrel coaxially thereof and facing the opposite end of the barrel, said opposite end of the barrel being open, a revoluble arm on which the barrel is mounted; and a holder supported by the arm co-axially of the barrel at said open end thereof and in alinement with the imnression holder and adapted to dispose a modeling material for translation thereof to the impression.

holder by centrifugal force when the arm is revolved.

4. A dental device of the class described comprising a barrel having a removable closure cap at one end, provided with means for removably supporting and disposing an impression holder within the barrel coaxially thereof and facing the opposite end of the barrel, said opposite end of the barrel being open, a revoluble arm on which the barrel is mounted; and a holder supported by the arm co-axially of the barrel at said open end thereof and in alinement with the impression holder and adapted to dispose a modeling material for translation thereof to the impression holder by centrifugal force when the arm is revolved, said modeling material holder including a tube fixed to the arm and an openended hollow cylinder removable from the tube and adapted when removed therefrom to be filled with a quantity of said material for the purpose first stated. I

NORMAN N. NECHTOW. 

